RotateCAPTCHA a novel interactive CAPTCHA design targeting mobile devices

Completely Automated Public Turing test to tell Computers and Humans Apart (CAPTCHA) is a challenge-response system test used on the web, designed to differentiate humans from automated computer systems. Most of the widely used CAPTCHA systems are designed with desktop users in mind hence lack the native look and feel when they are used on mobile devices. The reason is the way people interact with desktop/laptop computer using mouse and keyboard is different from the way they interact with mobile devices using touch and other gestures. Also, the screen size and the dimension of the viewing display plays a role in the interaction. Here, we present a novel CAPTCHA system designed for mobile devices and results of the usability study that we conducted with an implementation of the same. This CAPTCHA system is composed of multipart image reconstruction and orientation identification. Although, this is an intuitive task for humans, it is very hard to automate using a computer system. The main advantages of our system over traditional systems are native mobile look and feel, language/culture independent, and gesture-based interaction.